Generally speaking, this invention relates to a sample collection device, such as a sputum tube, useful for separating a sample to be examined into a heavy fraction and a light fraction. More particularly, this invention relates to a centrifuge sample collection tube which provides rapid access with less contamination to the heavy fraction at the bottom of the tube, without having to disturb or otherwise expose the upper lighter fraction in the tube. The device of the invention may be a conventional collection tube, modified by having an opening made therein at the bottom for receiving the second portion of the device of the invention here in the form of a plug. The plug is configured to be received into the opening in the bottom of the tube, and to complete or otherwise fill in the outline of the bottom of the tube left by the modified opening. The plug is configured, also, to be held in the bottom of the tube against displacement into or out of the opening, once it is correctly positioned in the opening.
The plug, in accordance herewith, has an annular generally vertical wall defining a central cavity for receiving the heavy fraction during the separation procedure, as described above. In addition, the plug includes an annular notch adjacent the bottom area of the plug for holding the plug against displacement inwardly. The arrangement of the plug is such that it provides a septum area for inserting a needle for removal of the heavy fraction contained in the central cavity, once centrifugation has taken place. Thus, the heavy fraction may be removed by insertion of a needle with syringe without disturbing or otherwise contaminating the upper fraction. It will be understood, further, that the upper fraction will not be exposed to contaminate the hands and/or syringe in such a removal process which would ordinarily be the case if the upper lighter fraction had to be decanted or otherwise removed prior to gaining access to the heavy fraction in the bottom of the tube, after centrifugation.
Other objects and advantages of this invention will now be apparent from the following description, the accompanying drawings, and the appended claims.